Micron-size polymer particles and inorganic particles are used as fillers and specimens in diverse fields, such as electrical and electronic materials, optical materials, paints, inks, construction materials, biological and pharmaceutical materials, and cosmetics.
In particular, particles of unusual, non-spherical shapes are capable of exhibiting various properties differing from those of spherical particles in terms of, for example, optical characteristics and tactile feel. Such particles have thus been the subject of active development efforts in recent years, and new applications are constantly emerging.
The inventors have worked thus far on the development of elliptical or needle-shaped polymer particles of high aspect ratio, and have discovered a variety of particles with characteristics superior to those of conventional spherical particles in terms of such properties as hiding power, light-diffusing ability and tactile qualities (Patent Documents 1 and 2). However, in this technical field, novel polymer particles continue to be developed in an effort to achieve still further improvements in characteristics.